A chaired professor of Southern history at the University of Alabama, Rable mined numerous archival collections in the North and South to produce a fascinating, evenhanded treatment of religion that spans theology to church and clerical history and beyond. He makes especially good use of denominational newspapers, including Catholic ones that have been overlooked in previous studies that focused more on Protestantism.

By 1850, one in seven Americans belonged to a church. Perhaps not surprisingly, on both sides of the Civil War, many “turned to religious faith to help explain the war’s causes, course and consequence,” Rable writes. “Many believers took a providential view of both daily life and wartime events.” In their view, “the Lord kept track of individual and collective sins, doling out victories and defeats according to a precisely calculated evaluation of the contending sides.”

Religion undoubtedly boosted morale and lengthened the war. Its close alliance with patriotism is a recurring theme throughout the book. A compelling example occurred on July 2, 1863, just before the Irish Brigade entered the renowned Gettysburg wheat field. Rable captures the scene: “Standing on a large rock, Father William Corby summoned the men to make a ‘sincere act of contrition’ and then sternly warned that the church would deny Christian burial to anyone who turned coward. With the soldiers kneeling, heads bowed, Corby stretched out his right hand offering the ancient Latin words of absolution.”

In the charged atmosphere of war, it was well nigh impossible for churches to advocate both abolition and pacifism. The Quakers, one of the historic peace churches (with the Mennonites and the Church of the Brethren), often found it difficult not to enlist in the Union Army. Complexities and contradictions confronted most religions in these days, and congregants sought to preserve church unity even in the midst of sectional conflict. Thus, for instance, Rable found that Southern Catholics remained “reticent” about the issue of secession.

Above all, “God’s Almost Chosen People” demonstrates the uncommon resilience of religious faith during times of crisis. Both general reader and scholar will find much here of value.

Roberts directs the journalism program at the State University of New York at Albany. Her books include “Dorothy Day and the Catholic Worker.”